Two different kinds of "protected"
A hidden photo is like a book moved to a high shelf: the library still catalogues it, anyone who looks up can see it, and the librarian will fetch it on request. An encrypted photo is a book written in a cipher only you can read: its location stops mattering, because possession no longer equals access.
Phones blur this distinction constantly. Lock screens, hidden albums, app PINs and disguised icons all feel like protection because they add steps. But steps are friction for the honest; readability is the only thing that stops the motivated. The question to ask of any privacy feature is simply: does it change what is displayed, or what is readable?
How each fails
Display rules fail loudly and completely: one tap into the Hidden album, one synced iPad, one backup opened on a laptop, one extraction — and everything is simply there, in the clear. There is no partial failure; the filter either holds attention away or it is over.
Encryption fails only at its edges: a guessable PIN, keys a vendor can hand over, or plaintext copies that never got cleaned up (camera-roll originals, Recently Deleted, old sync targets). Inside a correct boundary — strong key derivation, on-device keys, no plaintext leftovers — the content stays noise regardless of who holds the hardware. That is why the checklist for choosing a vault is really a checklist about edges.
The third layer: deniability
Encryption has one tell: it is visible. A locked container in plain sight concentrates attention and invites the direct demand — "open it." Deniable design removes the tell. Sealby stores all vaults in a uniform pool with no count and no directory; each PIN opens its own vault, and nothing distinguishes "you saw everything" from "there is more". Display rules hide from glances, encryption defends content, deniability defends the question of existence itself. Pick the layer that matches who you are actually protecting against.